In a book on David Bailey (Birth of the Cool) there are a couple of high-key portraits. He used a lighting tent - a technique borrowed from his mentor, Robert French. The maximum size I've seen is 48" cube on B&H, so I presume a scaled-up version is not commercially available. But the results from such a tent appear worth the effort to create/improvise it.
A few posts up, I described my high-key lighting setup which is essentially a "light wall" that can also be a "light corner".
If you want anything along the lines of a light tent for people, it's a simple matter of laying, say, 1/2" conduit across two stands and draping diffusion over the crossbar. Pretty simple to create, say, an 8' square which you light from behind, or setup in full sun with diffusion overhead.
With 4 stands (corners of the cube), three crossbars, and a lot of material, you can make a cube with an open-end for the shooter and a "roof".
I own all sorts of photo-designed diffusion fabrics, but when I was starting out with this look, I just hit the fabric store, carried some bolts out into the sun, and found something with the quality I liked. I still use that same fabric to this day to make very large diffusion walls.
Here's an example, in this case it was a large half-circle of conduit and a lot of diffusion fabric - just cheap fabric store nylon that was almost-sheer: